Eye state asymmetry during aquatic unihemispheric slow wave sleep in northern fur seals (Callorhinus ursinus)

• DOI: 10.1371/journal.pone.0217025
• Publication Date: 2019-05-22T17:32:47Z
• Authors: Jessica M. Kendal...; Alexei L. Vyssotski; Lev M. Mukhametov; Jerome M. Siegel; Oleg I. Lyamin
• Keywords: Fur seal; Sleep

Unihemispheric slow wave sleep (USWS) is a unique form of in which one brain hemisphere maintains low voltage electrical activity indicative waking while the opposite exhibits sleep. USWS present several marine mammals and some species birds. One proposed biological function to enable animal monitor environment detect predators or conspecifics. While asymmetrical eye state was often observed during behavioral birds mammals, electrophysiological (electroencephalogram, EEG) correlates between asymmetry EEG two cortical hemispheres have not been reliably established. This study examined association aquatic subadult northern fur seals (Callorhinus ursinus), taking advantage simultaneous visibility both eyes when were prone position. We found that contralateral sleeping closed on average 99.4±0.1% recording time. The opened briefly for 1.9±0.1 sec with rate 8.2±1.0 per min. open 24.8±2.5% time it no longer than 3 sec, 39.4±5.6% These data indicate seawater by having intermittent visual monitoring. Our findings document extent monitoring support idea allows vigilance. Thus, serves functions seal, facilitating movement vigilance, may also be case cetaceans.